An existing foldable back support holder is operable to support and hold a mobile electronic device at a desired inclined position. The existing foldable back support holder includes a main body, a kickstand and a conventional hinge assembly connecting the kickstand to the main body. With the conventional hinge assembly, the kickstand is pivotal relative to the main body to adjust an angle between the main body and the kickstand. For aesthetic reason, a gap formed between the kickstand and the main body is expected to be minimized when the existing foldable back support holder is in a fully folded state. However, the conventional hinge assembly may not satisfy such expectation.